October 4, 2013

Over the past two weeks, and again in the last two days, several areas in Nebraska have been hit with severe thunderstorms, including hail and high winds. While it is impossible to assess the damage and make harvest recommendations without evaluating individual fields, we can think about some general issues.

After corn grain reaches the dough stage, there is little yield impact other than harvest loss. Harvest loss will vary greatly depending upon damage level, stalk strength of hybrids, ear/kernel damage (mostly due to hail), root lodging, and stalk health. In fields that were already stressed during grain filling, stalks have been "cannibalized" to fill grain, leaving them hollowed out and much more susceptible to wind and hail. In addition, with many ears still upright and abundant moisture from the rains, sprouting has been reported in both storm-damaged and non-damaged corn. (See related CW article, Sprouting Corn Kernels on Hail-Damged Ears.)

Soybeans are even more susceptible to harvest loss, and even areas where wind and hail didn't do damage, rain can cause problems. Where the bean pods were dry, re-wetting and then re-drying often weakens the pods to the point where they "pop" open and seed scatters. Some varieties are more problematic than others, and fields should be scouted to schedule harvest on remaining soybean fields.

Harvesting damaged corn fields first, providing the grain is at realistic moistures, makes good sense. On many damaged fields it will pay to dry corn from the mid 20% moisture range, rather than risk increased harvest losses by waiting until grain is dry enough "to bin." In extreme situations, harvest direction can make a difference in how stalks "feed" into the combine head. Often, harvest loss is reduced by slowing down to allow the machine to work its magic. Stalk quality will continue to deteriorate, leaving the crop exposed to increasing damage from more weather as well as corn stalk and ear rot diseases due to increased moisture. (See related CW article, A Guide to Late Season Corn Stalk and Ear Rot Diseases.) Prompt harvest is the best defense against loss of ears and kernels.

Grain from storm-damaged fields is almost always variable in quality, moisture, and physical damage. This makes it advisable to NOT use minimum drying standards, but think carefully about how wet the wettest kernels are, rather than the average. Good continued aeration, and care not to do further damage in handling is critical. And, it would be the first grain to consider using or selling, as the storability may be compromised as well. (See related article, Storm-Damaged Corn: Testing and Feeding.)

Thinking about next year, storm-damaged fields often have the highest harvest loss. Especially given the corn/soy price relationship, it would be a great year to consider crop rotation. It allows many more timing, management, and chemical opportunities to prevent problems with volunteer in next year's crops, especially if we have a dry winter and spring.

Tom Hoegemeyer
Professor of Practice, Department of Agronomy